It is known that on board an aircraft, it is important to know certain information relating to the flight of the aircraft. Anemometric measuring techniques can be used to ascertain such information. It may notably concern parameters relating to the air around the aircraft, such as static pressure, dynamic pressure or total temperature. It may also concern parameters relating to the position of the aircraft in its environment, such as the speed of the aircraft, its angle of incidence or its angle of sideslip. The angle of incidence is the angle between the air flow direction and the horizontal trajectory of the aircraft, and the angle of sideslip is the angle between the air flow direction and the trajectory of the aircraft.
From the value of some of these parameters, it is possible to determine the value of certain others of these parameters. Also, to ascertain the value of all the anemometric parameters useful on board the aircraft, some of these anemometric parameters are measured, and the other parameters are deduced from these measurements.
Currently, the parameters on board the aircraft are measured, generally, by means of different probes that are placed outside the aircraft, on the outer skin of the latter.
It is also known to measure some of these anemometric parameters using a laser anemometer, as described for example in the document WO-2007/036662 which relates to a system for monitoring anemobaroclinometric parameters of an aircraft.
Although not exclusively, the present invention more particularly applies to the simultaneous determination of the angle of incidence and of the angle of sideslip of an aircraft.
It is known that a standard probe intended for measuring both the angle of incidence and the angle of sideslip, that is installed on one side of the aircraft, cannot provide sufficient measurements for directly calculating the values of said angles of incidence and of sideslip. In practice, the measurement, at any point of the aircraft (except in a horizontal plane that is parallel to the general plane of the supporting surface, and in a vertical longitudinal plane that is orthogonal to this horizontal plane), taken by an anemometric probe depends, in particular, simultaneously, on the angle of incidence and on the angle of sideslip. The duly taken measurement therefore corresponds to a combination of these two angles (of incidence and of sideslip) making an exact and independent determination of each of these angles impossible.